Hi all.
I have a yamaha 130hp saltwater series V4 which i love. however I had a mate around to service it (a qualified outboard mechanic) and when he removed the spark plug caps on 2 of the cylinder heads (one at a time) they had no effect on the performance of the engine. when he removed the other 2 caps (again one at a time) they nearly killed the engine. also the engine run generally rough as i was told it should sound like a sewing machine when running perfectly.
we checked the timing and all 4 cylinders are dead on TDC. ran a compression test and all compresson is perfect. visual inspection of the carbys showed they were still really clean.
so my questions are:
1) should the timing be spot on TDC for all cylinders?
2) could the timing be the reason for my rough running?
3) what the hell should i do about it?
Thanks guys, looks forward to nutting this one out.
Nick
I have a yamaha 130hp saltwater series V4 which i love. however I had a mate around to service it (a qualified outboard mechanic) and when he removed the spark plug caps on 2 of the cylinder heads (one at a time) they had no effect on the performance of the engine. when he removed the other 2 caps (again one at a time) they nearly killed the engine. also the engine run generally rough as i was told it should sound like a sewing machine when running perfectly.
we checked the timing and all 4 cylinders are dead on TDC. ran a compression test and all compresson is perfect. visual inspection of the carbys showed they were still really clean.
so my questions are:
1) should the timing be spot on TDC for all cylinders?
2) could the timing be the reason for my rough running?
3) what the hell should i do about it?
Thanks guys, looks forward to nutting this one out.
Nick
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